The aims of this research are to investigate the lecels of the low molecular weight UV absorbing components in serum of normal subjects and those with neoplastic diseases and to test the hypothesis that specific disease states can be characterized by distinctive high pressure liquid chromatographic (HPLC) profiles of nucleosides, their bases and other low molecular weight, UV absorbing compounds in serum. If the hypothesis is valid, then the profiles can be used clinically to detect and to monitor disease states and to assess the effectiveness of therapy. Our specific goals are to investigate both qualitative and quantitative changes in nucleosides and their bases in serum from patients with various types of neoplastic and other diseases, to determine the statistical validity and significance of the changes and to correlate the changes to specific disease states. In order to accomplish these goals, it is necessary to develop rapid, reliable HPLC techniques for the accurate analysis of nucleosides, their bases and other l0w molecular weight, UV absorbing constituents in serum and to determine normal values for the concentrations of these compounds in serum from subjects with no known disease states.